bug#8013: 23.2.93; png not available

[Uday S Reddy]

The libpng package I have installed is 1.2.37, which is the latest
version available on GnuWin32.

  http://gnuwin32.sourceforge.net/packages.html

libpng-version in Emacs is 10403.  So, it doesn't fit the bill.

Sean Sieger's pre-compiled Emacs distribution that I downloaded
doesn't seem to have the README.W32 file.  So, it has gone missing
somewhere.

I also wonder if it would be useful to provide diagnostic information
about package support somehow, e.g., with an optional argument to
image-type-available-p which prints diagnostic information.

Cheers,
Uday